This invention relates to a modulation effect device, and more particularly a modulation effect device capable of providing a desired modulation effect by utilizing a digital filter.
Prior art modulation effect device which has been used to apply such modulation effect to a musical tone signal generated from an electronic musical instrument etc. as vibrato, chorus and ensemble (symphonic chorus) is such analogue delay element as a BBD (backet brigade device) or a CCD (charge coupled device) and by modulating the shift clock applied to such a delay element, a phase (frequency)-modulated signal is produced by the delay element.
With the modulation effect device utilizing such analog delay element, however, since the dynamic range for the input signal to the analog delay element is narrow, there are such defects as a poor or small S/N ratio and a large noise. Where the modulation effect device is applied to an electronic musical instrument in which a musical tone signal is converted into a digital code, as the digital musical tone signal is one converted into an analog signal with a D/A converter and then inputted into the modulation effect device, it is necessary for a filter having a sharp cut-off characteristic to follow the D/A converter. Use of such filter not only makes it difficult to fabricate the circuit as an integrated circuit but also makes bulky the circuit.